March 22 (Reuters) - U.S. stocks looked set to open slightly lower on Wednesday, a day after Wall Street posted its biggest one-day fall since the November election, as investors fret about potential delays to President Donald Trump's pro-growth policies.

Trump on Tuesday tried to rally Republican lawmakers behind a plan to dismantle Obamacare, his first major legislation since assuming office in January.

Republican leaders aim to move the controversial legislation to the House floor for debate as early as Thursday, amid concerns over support from party lawmakers.

Some investors fear that if the healthcare reform act runs into trouble or takes longer-than-expected to pass, then Trump's tax reform policies may face setbacks.

"The markets were reminded yesterday the 'Trump trade' is not a one-way trade and there's room for disappointment as actions on tax cuts and infrastructure spending might not materializes as quickly as we want," said Anastasia Amoroso, global market strategist at J.P. Morgan Private Bank in Houston.

"The pronounced fall in yields across the world is not helping market sentiment at the moment either."

U.S. 10-year Treasury yields fell to three-week lows on Tuesday and the gap between U.S. and German 10-year government borrowing costs hit its narrowest since November.

The S&P 500 has run up about 10 percent since the election in November, spurred mainly by Trump's agenda of tax cuts and infrastructure spending, but valuations have emerged as a concern.

The benchmark index is trading at about 18 times forward earnings estimates against the long-term average of 15, according to Thomson Reuters data.

The last time the S&P 500 lost 1 percent or more in a day was on October 11.

"Given the full valuation and the long time that's passed since we've had a one percent down day, let alone a correction, a forward correction is a real possibility," said Amoroso.

Nasdaq 100 e-minis were down 2.25 points, or 0.04 percent, on volume of 45,312 contracts.

Oil prices also dipped and slipped back to three-month lows after data showed U.S. crude inventories rising faster than expected.

Gold prices rose to a three-week high and the dollar index , which measures the greenback against a basket of currencies, was at 99.87, near the six-week low of 99.64 reached on Tuesday.

Shares of financials, which suffered their worst daily drop since June, were lower in premarket trading. Bank of America , Goldman Sachs, JPMorgan, Citigroup and Wells Fargo were all down. The financial sector has been the best performing of the 11 major S&P sectors since Trump's election, up 18 percent.

Sears Holdings slumped 14.8 percent to $7.75 after the retailer warned on Tuesday about its ability to continue as a going concern after years of losses and declining sales.

Dow-component Nike was down 5.3 percent at $54.91, a day after the world's largest footwear maker's quarterly revenue missed expectations.

FedEx rose 2.9 percent to $197.87 after the package delivery company posted an optimistic outlook for margins in the near-term. (Reporting by Tanya Agrawal; Editing by Sriraj Kalluvila)